This invention relates to a cylinder head with a ceramic precombustion chamber for an internal combustion engine such as a diesel engine or the like.
Cylinder heads provided with ceramic precombustion chambers have been practically used for diesel engines in view of their excellent heat resistance and heat transfer coefficient. Such a cylinder head was disclosed in Japanese Patent Application Publication No. 61-42,096 as shown in FIG. 1. With the cylinder head 21 shown in FIG. 1, after a metal sleeve 24 is fitted on an outer circumference of a ceramic precombustion chamber 22 having an injection aperture so as to extend some way from an end surface of the precombustion chamber 22 on a side of a main combustion chamber, the metal sleeve 24 together with the ceramic precombustion chamber 22 is press-fitted into a cylinder head 27 and the extending portion of the metal sleeve is then cut away by machining.
With the cylinder head 21 with the ceramic precombustion chamber obtained as above described, however, even if only the extending portion of the metal sleeve 24 is cut off, it is very difficult to make the cut surface of the metal sleeve 24 flush with the surface of the precombustion chamber on the side of the main combustion chamber. As a result, when the cylinder head 21 with the ceramic precombustion chamber is mounted through a gasket 25 onto a cylinder block 26, a clearance would occur between the head gasket 25 and the surface of the ceramic precombustion chamber 22 on the side of the main combustion chamber so that the head gasket is exposed to burning gases to deteriorate in use. As a result, burned gases leak out of the main combustion chamber.